Quick Answer: Under California ADU law effective 2020 and updated through 2025, detached ADUs in San Jose require only a 4-foot minimum setback from side and rear property lines (AB 68/SB 13/AB 3182). No setback is required from an existing structure on the same lot. Front yard setbacks follow the underlying zone (typically 15-20 feet in residential zones). Maximum height: 16 feet within 4 feet of property line; up to 25 feet further back.
San Jose ADU Setback Requirements 2025 — Complete Guide
Helpful Resources:
| Setback Type | Detached ADU | Attached ADU | JADU |
|---|---|---|---|
| Side yard | 4 feet minimum | Same as primary dwelling | 0 feet (inside primary) |
| Rear yard | 4 feet minimum | Same as primary dwelling | 0 feet (inside primary) |
| Front yard | Per zone (typically 15-20 ft) | Per zone | Per zone |
| From existing structures | No setback required | Attached to house | Inside main house |
ADU Height Limits Near Property Lines in San Jose
- Within 4 feet of property line: Maximum 16-foot height
- Beyond 4 feet from property line: Maximum 25 feet (or 2 stories if farther than the required front setback)
- Exception: ADUs above a detached garage can be up to 25 feet if the garage was existing
ADU Size Limits in San Jose 2025
- Detached ADU maximum: 1,200 sq ft (no larger, regardless of lot size)
- Attached ADU maximum: 50% of primary dwelling square footage, up to 1,200 sq ft
- JADU maximum: 500 sq ft
- Studio/1-bedroom ADU minimum: No state-mandated minimum size in San Jose
What Changed in 2024-2025 California ADU Law
- AB 2221 (2022/effective 2023): ADUs within 4 feet of property line limited to 16 feet height; ADUs farther back can now be 2 stories
- SB 1211 (2024): Allows up to 8 detached ADUs on a multifamily lot (previously just 2). For single-family lots, still 1 ADU + 1 JADU
- No owner-occupancy requirement: California law bans local owner-occupancy requirements through 2025
Quartz Construction is San Jose’s ADU specialist. We handle permits, plans, and construction for detached and attached ADUs. Learn about ADU construction services. CSLB #1003436 | BBB A+ | 4.9 stars. Call (650) 749-7436.
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